<?php
class VerifycodeAction extends Action {
	
	//生成验证码图片
    public function index(){
		VerifycodeAction::getCode(4,60,20);
    }
	
	function getCode($num,$w,$h) {
	    ini_set('display_errors', 'Off');
		$code = ""; 
	    for ($i = 0; $i < $num; $i++) { 
	        $code .= rand(0, 9); 
	    } 
	    //4位验证码也可以用rand(1000,9999)直接生成 
	    //将生成的验证码写入session，备验证时用 
	    session("verifycode",$code);
	    //创建图片，定义颜色值 
	    header("Content-type: image/PNG"); 
	    $im = imagecreate($w, $h); 
	    $black = imagecolorallocate($im, 0, 0, 0); 
	    $gray = imagecolorallocate($im, 200, 200, 200); 
	    $bgcolor = imagecolorallocate($im, 255, 255, 255); 
	    //填充背景 
	    imagefill($im, 0, 0, $gray); 
	    //画边框 
	    imagerectangle($im, 0, 0, $w-1, $h-1, $black); 
	    //随机绘制两条虚线，起干扰作用 
	    $style = array ($black,$black,$black,$black,$black, 
	        $gray,$gray,$gray,$gray,$gray 
	    ); 
	    imagesetstyle($im, $style); 
	    $y1 = rand(0, $h); 
	    $y2 = rand(0, $h); 
	    $y3 = rand(0, $h); 
	    $y4 = rand(0, $h); 
	    imageline($im, 0, $y1, $w, $y3, IMG_COLOR_STYLED); 
	    imageline($im, 0, $y2, $w, $y4, IMG_COLOR_STYLED); 
	 
	    //在画布上随机生成大量黑点，起干扰作用; 
	    for ($i = 0; $i < 80; $i++) { 
	        imagesetpixel($im, rand(0, $w), rand(0, $h), $black); 
	    } 
	    //将数字随机显示在画布上,字符的水平间距和位置都按一定波动范围随机生成 
	    $strx = rand(3, 8); 
	    for ($i = 0; $i < $num; $i++) { 
	        $strpos = rand(1, 6); 
	        imagestring($im, 5, $strx, $strpos, substr($code, $i, 1), $black); 
	        $strx += rand(8, 12); 
	    } 
	    imagepng($im);//输出图片 
	    imagedestroy($im);//释放图片所占内存 
	}
    
    
}